Electric Shower

For any certainty you will need an electrician to test the supply to the unit. That's the breaker, rcd, cable and switch. If all this is still good then the shower unit is to blame and needs to be replaced. It is unlikely that anyone but a qualified sparky will be able to make the above determination. Kind regards Martin

Depends on a few things how old is the shower? Can you get spares for it? It may be cost effective to repair it or it may be more economical just to replace it. Bear in mind if it is old and you don’t get the same unit the pipe work may need adjusting which would add to the cost.